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Cumulus-oocyte complexes from hormone-stimulated 3-4-week-old (n=43) and 6-7-week-old (n=12) prepubertal lambs were matured in vitro and incubated with unsorted, or X- or Y-spermatozoa separated with a high-speed cell sorter (SX MoFlo)frozen-thawed. Presumptive zygotes were then cultured to the blastocyst stage, and transferred to recipients fresh or after cryopreservation (frozen). Oocyte cleavage was higher (p <0.05) with unsorted (515/926, 55.6%) than X- or Y-spermatozoa (261/672, 38.8% and 229/651, 35.2%, respectively) and blastocyst formation (% zygotes) by Day 9 of in vitro culture was lower (p <0.05) for X- (102/261, 39.1%) than unsorted spermatozoa (249/515, 48.3%), but did not differ between Y-spermatozoa (103/229, 45.0%) and unsorted spermatozoa, or between X- and Y-spermatozoa (p >0.05). For fresh embryos, survival to term was 50.0% (3/6) for unsorted, 0.0% (0/6) for X- and 16.7% (1/6) for Y-spermatozoa-derived embryos (p >0.05), and for frozen embryos was 4.0% (2/50) for unsorted, 9.1% (2/22) for X- and 2.9% (1/34) Y-spermatozoa-derived embryos (p >0.05). Of the two lambs born from X-spermatozoa-derived embryos, one was female (50%), and from the two Y-spermatozoa-derived lambs, both were male (100%), demonstrating that lambs can be produced after the transfer of fresh and cryopreserved IVP embryos derived from prepubertal lamb oocytes and frozen-thawed sex-sorted sperm.  相似文献   
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An absorbed enzyme immunoassay (EIA) test for Johne's disease in cattle was developed in which absorption of cross-reacting antibodies occurred as a rapid reaction in solution rather than overnight with whole organisms and a subsequent centrifugation step. Total test time was reduced to less than 2 h with a minimum of manipulations. The test was evaluated in cattle herds from Johne's disease-endemic and Johne's disease-free regions of Australia. Specificity was 99.8%. Calculations of sensitivity were affected by the history of the herd under test. However, the EIA detected in excess of 80% of animals before onset of clinical disease and 65% of faecal shedders were EIA positive on, or before, first detection of Mycobacterium paratuberculosis in their faeces. The test should aid epidemiological studies and be a useful tool in the management and control of Johne's disease.  相似文献   
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The presence of endothelin, a vasoconstrictor peptide, in the hypothalamus and posterior pituitary suggests that it also regulates neural and other nonvascular target cells. In pituitary gonadotrophs, low doses of endothelin evoked oscillations in the intracellular calcium concentration, and high doses induced a biphasic calcium response. Mobilization of intracellular calcium predominated during the spike phase of the calcium response to endothelin, whereas calcium entry through dihydropyridine-sensitive channels contributed to both the spike and plateau phases of the calcium response. Endothelin was a potent as hypothalamic gonadotropin-releasing hormone (GnRH) in stimulation of gonadotropin release in perifused pituitary cells. Endothelin bound specifically to pituitary cells with a dissociation constant of 70 picomolar, and induced rapid formation of inositol trisphosphate and diacyglycerol. Although intracellular calcium concentration and gonadotropin secretory responses to endothelin were independent to the GnRH receptor, endothelin and GnRH appeared to have a common signal transduction mechanism. These observations suggest that endothelin can act as a neuropeptide to regulate anterior pituitary function.  相似文献   
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Objectives To review the clinicopathological findings in naturally-occurring, histopathologically confirmed cases of feline infectious peritonitis in client-owned cats in Sydney, Australia, with the purpose of identifying factors assisting in the diagnosis of this complex disease syndrome and to characterise the disease as it occurs in this region.
Design Retrospective clinical study: the clinical records of all cats with histopathologically confirmed feline infectious peritonitis at the University Veterinary Centre Sydney and a private cat hospital in Sydney between 1990 and 2002 were reviewed for signalment, history, physical findings, diagnostic test results and the distribution of histological lesions throughout the body at necropsy.
Results Forty-two cats met the inclusion criteria. Significant features of this study that unique to the contemporary literature are i) the over-representation of certain breeds (Burmese, Australian Mist, British Shorthaired, and Cornish Rex) and the under-representation of other breeds (Domestic Shorthaired, Persian); ii) the overrepresentation of males; iii) the tendency for effusive disease in Australian Mist cats and non-effusive disease in Burmese; iv) the even age distribution of disease seen in cats older than 2 years-of-age; and v) the presence of fulminant immune-mediated haemolytic anaemia in two cats in this study.
Conclusion The study highlights the diverse range of clinical manifestations and the complexities experienced by clinicians in diagnosing this fatal disease. Some aspects of the epidemiology and clinical manifestations of feline infectious peritonitis appear different to the disease encountered in Europe and North America, most notably the over-representation of specific breeds and the presence of immune-mediated haemolytic anaemia.  相似文献   
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An enteric infection in cockatoos associated with a 30 nm diameter enterovirus-like agent seen in faeces and intestinal epithelial cells is described. The disease is characterised by intractable, profuse, mucoid diarrhoea, weight loss, dehydration and death. Lesions in the intestine consist of villous atrophy, villous fusion, enterocyte hyperplasia and, in some cases, chronic inflammation. Affected birds so far examined have concurrent psittacine beak and feather disease.  相似文献   
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